This invention relates to the conversion of a vehicle wheel from passive to driven drive as when converting a vehicle between two-wheel and four-wheel, and more particularly it relates to the manner of providing selective clutch ring engagement as between a vehicle""s axle and a wheel hub for achieving the conversion.
A common arrangement for a two-wheel/four-wheel drive vehicle is with the two rear wheels in permanent drive and the front wheels convertible as between passive where the drive train is disconnected from the front wheels (the front wheels passively roll on a roadway as the vehicle is driven by the rear wheels), and driven where the front propellor shaft and front axles are connected to the front wheels so as to be driven by the vehicle engine.
To achieve the conversion it has been common to extend the front wheel axles into and through the wheel hubs to the outboard side of the wheel whereat a clutch ring is axially moved between engagement with one of the axle and wheel hub and, alternatively, engagement with both. A more recent improvement to the conversion process is the reconfiguration of the wheel hub to provide a mounting for the wheel hub to the vehicle frame or suspension that exposes a hub portion inboard of the wheel and adjacent an axle portion, e.g., at the CV joint. A clutch ring and actuator at this inboard end provide the desired engagement/disengagement of the wheel hub and drive axle. See the commonly owned U.S. Pat. No. 5,740,895.
A further consideration to the mounting arrangement is the bearings that provide rotation as between the vehicle frame (suspension) and the wheel hub. These bearings are placed under axial compression and locked to prevent undesired operating clearances. This axial compression and locking is desirably provided at the internal end, i.e., whereat the clutch ring engagement is provided. Prior designs for achieving both have involved the provision of a coupler that is rotatably fixed to the inboard end of the wheel hub adjacent the support bearings, and in cooperation with the coupler, a lock mechanism providing both axial compression and locked engagement of the coupler against the bearing. The coupler includes external splines adjacent and matched to splines on the axle which are selectively engaged by a clutch ring to thereby engage and disengage the axle from the wheel hub.
It is an objective of the present invention to separate the features of clutch ring engagement and bearing compression while simplifying the manner of clutch ring actuation.
In a preferred embodiment, the wheel bearings are mounted to the outer diameter of an inwardly extended portion of the wheel hub (sometimes referred to as the spindle portion of the wheel hub) and the inboard end of the spindle portion is turned or roll formed directly against the inner race of the bearings to apply both the desired compression and lock the bearings in the compressed condition.
The wheel hub is cylindrical and the inner diameter of the spindle portion, intermediate the ends, is fitted with bearings that provide rotatable support for the axle. The inner diameter at the extreme inboard end of the spindle portion is configured to have a spaced apart relation with the axle and the spaced apart interfaces of the spindle portion and axle are provided with splines. A clutch ring resides in the spacing and is axially slidable (via an actuator) relative to the splines to produce the desired engagement and disengagement as between the spindle portion of the wheel hub and axle. It is to be noted that the bearing retention is provided at the exterior wall of the cylindrical spindle portion and the clutch ring engagement is independently provided at the interior wall.
The invention will be more fully appreciated upon reference to the following detailed description having reference to the accompanying drawings.